Formulations of viloxazine

ABSTRACT

Modified release formulations of viloxazine and methods of administering the same are disclosed. High-drug load formulations of viloxazine are further disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 15/605,108, filed May 25, 2017, which is aContinuation Application of U.S. patent application Ser. No. 15/172,955,filed Jun. 3, 2016, now U.S. Pat. No. 9,662,338, which is a ContinuationApplication of U.S. patent application Ser. No. 13/761,757, filed Feb.7, 2013, now U.S. Pat. No. 9,358,204, which claims the benefit ofpriority to U.S. Provisional Application No. 61/596,458, filed Feb. 8,2012. The contents of these applications are herein incorporated byreference in their entirety.

BACKGROUND OF INVENTION

Viloxazine hydrochloride, (±)-2-[(2-ethoxyphenoxy)methyl]morpholinehydrochloride (Structural Formula 1), is a racemic compound with twostereo isomers (R-viloxazine and S-viloxazine). The molecular weight ofthe hydrochloride salt is 273.8 with a conversion factor for viloxazinebase to viloxazine hydrochloride of 1.154.

Structural Formula 1: Viloxazine Hydrochloride

The pharmacokinetics of viloxazine have been evaluated in six epilepticpatients following an intravenous infusion and an oral dose bothequivalent to 200 mg of viloxazine base (E. Pisani et al.Psychopharmacology (1986) 90: 295-298). The absolute oralbioavailability was 85% (±14%, standard deviation). The drug was rapidlyabsorbed following oral administration with a tma_(x) of approximately 2hours. The observed elimination half-life was 4.3 hours (±1.5 hours,standard deviation).

Viloxazine was previously marketed in several European countries for thetreatment of major depressive disorder (MDD). Viloxazine is an inhibitorof the reuptake of norepinephrine, but may also enhance the release ofserotonin from neuronal stores. The typical “immediate release” oraldose of viloxazine in MDD, expressed as viloxazine base, was 200 mg-300mg daily given in 2 to 3 divided doses; in certain cases the daily dosewas increased to 600 mg (Vidal® pp 2116-2117 (2007)).

Due to the potentially high therapeutic dose, weakly basic nature of themolecule, and a relatively high in vivo clearance rate in humans,viloxazine presents challenges for developing an extended releaseformulation. These, and other, challenges have been overcome by theformulations of the instant invention.

SUMMARY OF THE INVENTION

Viloxazine hydrochloride, (±)-2-[(2-ethoxyphenoxy)methyl]morpholinehydrochloride, is a racemic compound with two stereo isomers(R-viloxazine and S-viloxazine). In silico physicochemical properties ofviloxazine base, calculated using ACD Labs software (product release8.08), include: a pK_(a) value of 8.47, a Log P value of 1.10, and anintrinsic solubility value of 2.3 mg/mL for the base. The hydrochloridesalt of viloxazine exhibits an aqueous solubility at 37° C. of 78 mg/mL.

In one embodiment, the invention is directed towards modified releaseformulations of viloxazine. In another embodiment of the invention, themodified release formulation is an extended release formulation. In yetanother embodiment, the modified release formulation is a pulsatilerelease formulation. The pulsatile release may be achieved using acombination of an extended release (XR) component with a delayed release(DR) component, or immediate release (IR) component with an extendedrelease (XR) component, or IR component with a DR component, or IRcomponent with an XR and DR components.

In another embodiment of the invention, modified release formulations ofviloxazine with a high drug load are provided. These formulationscontain an amount of viloxazine that is from about 25% (w/w) to about75% (w/w). A further embodiment covers a dosage form comprising theformulation of the current invention in the form of tablets, capsules,beads, granules, powders, caplets, troches, sachets, cachets, pouches,gums, sprinkles, solutions and suspensions. The tablets may be osmotictablets, matrix tablets, bi- and multilayer tablets, fast disintegratingtablets, mini-tablets, and other type of tablets commonly used in theart, or a combination thereof.

The capsules may contain pellets, beads, tablets, mini-tablets,granules, powders, and/or non-aqueous or partially non-aqueous liquidfill. Capsules may also be soft gelatin capsules comprising non-aqueousor partially non-aqueous liquid fill. The formulation may be alsopresented in the form of pellets in a capsule, where the capsule can beopened and the pellets sprinkled onto soft food or in a liquid, which isthen swallowed.

In yet another embodiment, a formulation is provided comprisingviloxazine or a pharmaceutically acceptable salt thereof, and at leastone of an extended release component and a delayed release component.The formulation may comprise from 25% (w/w) to 75% (w/w) of viloxazine.Further, the formulation may comprise 10 mg to 800 mg of viloxazine,preferably viloxazine hydrochloride.

The extended release formulation may comprise a release rate controllingcompound and at least one pharmaceutically acceptable excipient. Therelease rate controlling compound may be either a hydrophilic compoundor a hydrophobic compound, and preferably incorporated in an amount offrom 5% (w/w) to 65% (w/w) of the formulation.

Exemplary hydrophilic compounds include hydroxypropyl cellulose,hydroxypropyl methyl cellulose, methyl cellulose, polyethylene oxide,acacia, acrylic acid derivatives, alginic acid, its salts andderivatives thereof, hydroxyethyl cellulose, povidone, carrageenan,carboxymethylcellulose, tragacanth, polyvinyl alcohol, xanthan gum, andcombinations thereof. Exemplary hydrophobic compounds include ethylcellulose, cellulose acetate, cellulose acetate butyrate, waxes,hydrogenated vegetable oils, glyceryl behenate, glycerylpalmitostearate, PEG glyceryl esters, poly(ethyl acrylate-co-methylmethacrylate) ethyl acrylate methyl methacrylate copolymer, poly (ethylacrylate-co-methyl methacrylate-cotrimethylammonioethyl methacrylatechloride), polyvinyl acetate, cellulose acetate propionate, andcombinations thereof.

The formulation may comprise a matrix core, wherein the matrix corecomprises an admixture of viloxazine and the release rate controllingcompound. The core comprising viloxazine may have a coating of thehydrophobic compound on top of the core. Alternatively, the corecomprising viloxazine may have a coating of an enteric compound on topof the core.

The formulation may further comprise a delayed-release coatingcomprising an enteric compound and/or at least one additionalviloxazine-containing component selected from an immediate releasecomponent, an extended release component and a delayed release componentcomprising an enteric compound. The delayed release component maycomprise at least one core comprising viloxazine and a coating of theenteric compound on top of the core(s).

Each component of the formulation may be in the form of a layer and/or aplurality of particles. The formulation may thus comprise an extendedrelease component, an immediate release component and a delayed releasecomponent. As well, the formulation may comprise at least two extendedrelease components, wherein each extended release component has its ownrate of release.

Enteric compounds may be selected from a group consisting of poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid), poly(methacrylic acid-co-methyl methacrylate), hydroxypropyl methylcelluloseacetate succinate, hydroxypropyl methylcellulose phthalate, celluloseacetate phthalate, shellac, and zein and comprise from 5% (w/w) to 40%(w/w) of the formulation.

Further, the present invention provides extended release dosageformulations of viloxazine base, and/or its salts, stereoisomers andpolymorphs thereof for administration to a mammal in need thereof forthe treatment of CNS disorders, including but not limited to thetreatment of ADHD and major depressive disorders. The formulations maybe administered once a day (QD) or twice a day (BID) and can result in areduced level of at least one undesirable side effect as compared to thesame amount of viloxazine administered as an immediate releaseformulation BID or TID. The undesirable side effects may be, forexample, gastrointestinal side effects (e.g., dyspepsia, nausea andvomiting) and neurological side effects (e.g., sleep disturbances,insomnia, abnormal dreams). The mammal being treated may be a humanchild or adult administered the viloxazine formulation in a dose of from10 mg to 800 mg of viloxazine.

The administration of the present formulations provides for a maximumsteady state plasma concentration (Cmax) of viloxazine which is higherthan the minimal therapeutically effective concentration and is in therange of 50% to 125% relative to the maximum plasma concentrationproduced by administration of viloxazine as an IR formulation BID orTID. The formulations also provide for relative steady state area underthe viloxazine plasma concentration time profiles for a 24 hour dosinginterval (AUCtau) in the range of 80% to 125% as compared to viloxazineadministered as an immediate release formulation TID or BID.

In an additional embodiment, the invention also provides a dosage formof viloxazine that can provide therapeutic levels of the drug for theperiod of time from about 4 hours to about 24 hours, preferably fromabout 6 hours to 16 hours, and most preferably from about 8 hours to 16hours.

Further, the present invention provides extended release dosage formsthat overcome the surprising lower mean relative bioavailabilityobserved in a clinical study. As well, formulations of the instantinvention may be characterized by a lower incidence of the adverseeffects including but not limited to gastrointestinal and neurologicalside effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the mean dissolution profiles (n=3) of a 200 mg dosestrength tablet (PD0348-005) at pH 1.1 and pH 6.8 (Example 1).

FIG. 2 shows the effect of drug load on the mean dissolution profiles(n=3) of 200 mg dose strength tablets (PD0348-005 (35% w/w), PD0348-069(40% w/w) and PD0348-071 (45% w/w)) at pH 6.8 (Example 2).

FIG. 3 shows the mean dissolution profiles (n=3) of a 200 mg dosestrength tablet (PD0348-015) at pH 1.1 and pH 6.8 (Example 3).

FIG. 4 shows the mean dissolution profiles (n=3) of a 200 mg dosestrength tablet (PD0348-041) at pH 1.1 and pH 6.8 (Example 4).

FIG. 5 shows the mean dissolution profile (n=3) of 200 mg dose strengthpellets (PD0348-114A) at pH 6.8 (Example 5).

FIG. 6 shows the mean dissolution profile (n=3) of 165 mg dose strengthpellets (PD0354-004C) at pH 6.8 (Example 6).

FIG. 7 shows the mean dissolution profiles (n=3) of 200 mg dose strengthpellets (PD0354-008A (8% w/w) and PD0354-008B (13% w/w)) at pH 6.8(Examples 7-9).

FIG. 8 shows the mean dissolution profiles (n=3) of 200 mg dose strengthpellets (PD0354-175A (5% w/w), PD0354-175B (7.5% w/w) and PD0354-175C(10% w/w)) at pH 6.8 (Examples 7-9).

FIG. 9 shows the mean dissolution profiles (n=3) of 200 mg dose strengthpellets (PD0360-007A (14% w/w) and PD0360-007B (18% w/w)) at pH 6.8(Examples 7-9).

FIG. 10 shows the mean dissolution profiles (n=3) of 200 mg dosestrength pellets (PD0377-006B) at pH 6.8 (Example 10).

FIG. 11 shows a mean dissolution profiles (n=6) of 150 mg dose strengthencapsulated pellets (PD0380-191, PD0383-192 and PD0383-035) at pH 6.8(Example 11).

FIG. 12 shows the effect of sodium chloride concentration on thesolubility of viloxazine hydrochloride in water at room temperature and37° C. (Example 12).

FIG. 13 shows the effect of chloride ion on the mean dissolutionprofiles (n=3) of 200 mg dose strength pellets (PD0354-076C) at pH 6.8(Example 12).

FIG. 14 shows the mean dissolution profiles (n=12) for the IR capsule,ER-1, ER-2 and ER-3 formulations of Example 14.

FIG. 15 shows the mean viloxazine plasma profiles obtained in a pilot PKstudy (n=21 healthy subjects) for the encapsulated IR, ER-1, ER-2 andER-3 formulations of Example 14.

FIG. 16 shows the plasma profiles obtained in a pilot PK study (n=21healthy subjects) for the IR capsule formulation for RS viloxazine,R-viloxazine and S-viloxazine (Example 16).

FIG. 17 shows the mean plasma profiles obtained in a pilot PK study(n=21 healthy subjects) for the ER-2 formulation for RS viloxazine,R-viloxazine and S-viloxazine (Example 16).

FIG. 18 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 50 mg every 8 hours daily, to theextended-release compositions of Example 17(a).

FIG. 19 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 75 mg twice daily (8 hours apart), tothe extended-release compositions of Example 17 (b).

FIG. 20 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 75 mg twice daily (10 hours apart), tothe extended-release compositions of Example 17(b).

FIG. 21 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 75 mg twice daily (8 hours apart), tothe extended-release compositions of Example 17(c).

FIG. 22 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 50 mg every 8 hours daily, to theextended-release composition of Example 18.

FIG. 23 shows simulated viloxazine steady state plasma profilescomparing an IR formulation dosed 50 mg every 8 hours daily to a 150 mggastric retentive extended-release tablet dosed once daily (Example 19).

FIG. 24 shows the mean dissolution profile (n=12) at pH 6.8 for theimmediate release capsule formulation of Example 15 compared to the meandissolution profile (n=3) of the extended release pellet formulationPD0348-175B (Example 25).

FIG. 25 shows the mean dissolution profile (n=3) of 150 mg dose strengthpellets (PD0387-096) at pH 6.8 (Example 28).

FIG. 26 shows the mean dissolution profile (n=3) of 150 mg dose strengthpellets (PD0387-119) at pH 6.8 (Example 29).

DEFINITIONS

Unless otherwise specified, “a” or “an” means “one or more” in thepresent application.

The term “Viloxazine,” unless specified otherwise, means(RS)-2-[(2-ethoxyphenoxy)methyl]morpholine or a pharmaceuticallyacceptable salt or ester thereof, any polymorph thereof as well asvariable mixtures of the R and S enantiomers or either one of the R or Senantiomers in a substantially pure form.

An “immediate release formulation” refers to a formulation that releasesgreater than or equal to 80% by weight of the active pharmaceuticalagent in less than or equal to 1 hour.

The term “modified release” encompasses any mode of release that isdifferent from an immediate release.

In the current application, the term “enteric compound” is used to meana compound having solubility that is pH-dependent.

The term “particles”, as used herein, includes, without any limitationson the nature and size thereof, any particles, spheres, beads, granules,pellets, mini-tablets, particulates.

The term “extended release” refers to at least 80% of the drug substancebeing released from the formulation over a period of time of at least 2hours either in vitro, as in a dissolution test, or in vivo followingoral ingestion of the drug containing entity.

The term “delayed release” refers to a formulation where there issubstantially no release of the drug substance at a pH below 4.5, butthe drug substance is released when the formulation is exposed to a pHof 4.5 or above.

The term “core” refers to the internal foundation of a structural unit(e.g., a bead) with or without drug.

The term “pharmaceutically acceptable excipient” refers to thosesubstances that are well accepted by the industry and regulatoryagencies such as those listed in monographs published in compendia suchas USP-NF, Food Chemicals Codex, Code of Federal Regulations (CFR), FDAInactive Ingredients Guide and in 21 CFR parts 182 and 184 that listssubstances that are generally regarded as safe (GRAS) food ingredients.

The term “high drug load” for a drug substance in the currentapplication applies to the formulations where the drug substance in thecomposition represents at least 25% (w/w).

“Soluble drug substance” is defined as per the USP definition forsoluble substances—1 part of substance is soluble in 10 to 30 parts ofsolvent.

For the purpose of this application, the terms “sieve size” or “meshsize” are used interchangeably and follow the designations of the USStandard sieves.

DETAILED DESCRIPTION OF THE INVENTION

The formulations of the instant invention provide modified releasecompositions of viloxazine comprising viloxazine, at least one releaserate controlling compound or an enteric compound, or a combinationthereof, and at least one pharmaceutically acceptable excipient.Further, the invention provides modified release formulations ofviloxazine with a high drug load.

The modified release formulations of viloxazine exhibit an XR profile,or a DR profile, or a combination of an XR and a DR profile, or anycombination of these with an IR profile. In some embodiments, theformulations may exhibit a pulsatile release profile. These specificrelease profiles are achieved by formulating viloxazine with at leastone of a release rate controlling compound and/or an enteric compound,and at least one excipient in a variety of inventive formulations.

The release rate controlling compounds of the current invention may beselected from hydrophilic rate controlling compounds and hydrophobicrate controlling compounds. The following non-limiting examples of suchcompounds are provided below.

Hydrophilic compounds: hydroxypropyl cellulose, hypromellose(hydroxypropyl methyl cellulose), methyl cellulose, polyethylene oxide,acacia, acrylic acid derivatives, alginic acid (and its salts andderivatives thereof), hydroxyethyl cellulose, povidone, carrageenan,carboxymethylcellulose, tragacanth, polyvinyl alcohol, xanthan gum andcombinations thereof.

Hydrophobic compounds: ethyl cellulose, cellulose acetate, celluloseacetate butyrate, waxes (e.g., carnauba wax, microcrystalline wax),hydrogenated vegetable oils, Compritol 888 ATO (glyceryl behenate),Precirol ATO 5 (glyceryl palmitostearate), PEG glyceryl esters such asGelucire 50/1, EUDRAGIT® NE 30 D or EUDRAGIT® NM 30 D (poly(ethylacrylate-co-methyl methacrylate) ethyl acrylate methyl methacrylatecopolymer), EUDRAGIT® RS and EUDRAGIT® RL (poly (ethylacrylate-co-methyl methacrylate-cotrimethylammonioethyl methacrylatechloride)), polyvinyl acetate, cellulose acetate propionate, andcombinations thereof.

The enteric compounds of the current invention may be selected from thefollowing non-limiting list of such compounds:

Enteric compounds: EUDRAGIT® FS 30 D (poly (methyl acrylate-co-methylmethacrylate-co-methacrylic acid)), EUDRAGIT® L 30 D-55, EUDRAGIT® L andEUDRAGIT® S (poly (methacrylic acid-co-methyl methacrylate)),hydroxypropyl methylcellulose acetate succinate, hydroxypropylmethylcellulose phthalate, cellulose acetate phthalate, shellac, zein,and combinations thereof.

The release rate controlling compounds, enteric compounds orcombinations thereof may be included into the formulation in the amountof from 5% to 65%, preferably in the amount of from 5% to 55%, mostpreferably in the amount of from 5% to 50%, by weight of theformulation.

Compounds that can be used as release rate controlling coatings include:cellulose esters, cellulose acetate, cellulose acetate butyrate, ethylcellulose, EUDRAGIT® RS and EUDRAGIT® RL (poly (ethyl acrylate-co-methylmethacrylate-cotrimethylammonioethyl methacrylate chloride)), EUDRAGIT®NE 30 D or EUDRAGIT® NM 30 D (poly(ethyl acrylate-co-methylmethacrylate)), ethyl acrylate methyl methacrylate copolymer, polyvinylacetate and combinations thereof.

In addition, the following enteric compounds can be used in a coating toprovide a delay in the release profile: EUDRAGIT® FS 30 D (poly (methylacrylate-co-methyl methacrylate-co-methacrylic acid)), EUDRAGIT® L 30D-55 (methacrylic acid-ethyl acrylate copolymer dispersion), EUDRAGIT® Land EUDRAGIT® S (poly (methacrylic acid-co-methyl methacrylate)),hydroxypropyl methylcellulose acetate succinate, hydroxypropylmethylcellulose phthalate, cellulose acetate phthalate, shellac, zein,and combinations thereof.

The application of a release rate controlling compound coating or anenteric compound coating is achieved using standard coating techniquessuch as spraying, dipping, casting, coating solvent evaporation, moldingor compression coating.

The release rate controlling and enteric compounds described above maybe used to prepare a variety of modified release systems:

A) Matrix systems, wherein an active pharmaceutical ingredient(viloxazine, or viloxazine and an additional active); at least onerelease rate controlling compound and at least one pharmaceuticallyacceptable excipient are homogeneously intermixed to form a matrix.Hydrophilic and hydrophobic compounds listed above may be used toprepare these viloxazine-containing matrices. These matrices may bepresented in the form of matrix tablets, matrix multiparticulates, or inthe form of a layer coated onto a substrate.

Matrix tablets may be in the form of multiple layer tablets (e.g.,bilayer or tri-layer tablets), tablet within a tablet, encapsulatedmini-tablets or a tablet of compressed modified release particles. Thesematrix systems may be coated with release rate controlling compoundsand/or the enteric compounds to add additional release rate controllingcharacteristics or a delayed release characteristics to the extendedrelease profile of a formulation.

B) Drug-layered systems that comprise an inert core and at least onedrug-containing layer coated onto this core. The drug containinglayer(s) may be further coated with a layer of a release ratecontrolling compound selected from those listed above. If thedrug-containing layer of the drug-layered system does not contain anyrelease rate controlling compounds and is of an immediate releasenature, then a release rate controlling coating is necessary forachieving the modified profiles of the current invention.

In cases where the drug-containing layer is an extended release matrixlayer described above, the release rate controlling coating is optionaland allows for additional modification of the release profile. Forexample, the coating may be used to modulate the release (slowinitially, faster later; or fast initially, slower later), or to providea delay in the release. In particular the release rate controllingcoatings can include: cellulose esters, cellulose acetate, celluloseacetate butyrate, ethyl cellulose, EUDRAGIT® RS and EUDRAGIT® RL(poly(ethyl acrylate-co-methyl methacrylate-cotrimethylammonioethylmethacrylate chloride)), EUDRAGIT® NE 30 D or EUDRAGIT® NM 30 D(poly(ethyl acrylate-co-methyl methacrylate)), ethyl acrylate methylmethacrylate copolymer, polyvinyl acetate, cellulose acetate propionate,and combinations thereof.

In addition, the following enteric compounds can be used in a coating toprovide a delay in the release profile: EUDRAGIT® FS 30 D (poly(methylacrylate-co-methyl methacrylate-co-methacrylic acid)), EUDRAGIT® L 30D-55 (methacrylic acid-ethyl acrylate copolymer dispersion), EUDRAGIT® Land EUDRAGIT® S (poly(methacrylic acid-co-methyl methacrylate)),hydroxypropyl methylcellulose acetate succinate, hydroxypropylmethylcellulose phthalate, cellulose acetate phthalate, shellac zein,and combinations thereof.

In some embodiments of the invention, a core may not be inert butcompositionally be of pure drug substance or a mixture of the drugsubstance and one or more pharmaceutically acceptable excipientproducing an IR core. In such a case, the cores can undergo furtherprocessing as described above for inert cores to produce the desiredextended release formulation.

Processes that may be used to produce formulations of this embodimentcomprising a drug-containing core include solution or dry powder druglayering, compression coating, hot melt coating, supercritical fluidcoating, electrostatic spray coating, agglomeration, granulation,pelletization, roller compaction, tablet compression, wet granulationwith extrusion and spheronization, hot melt extrusion, and injectionmolding. Roller compaction, tablet compression, and the extrusion withspheronization processes are particularly helpful for the manufacturingof formulations with a high drug load.

Without putting any limitations thereon, exemplary formulations of thepresent invention having different modified pharmacokinetic (PK)profiles for viloxazine are as follows:

-   -   Mixed IR and XR particles in a capsule, compressed tablet or any        other dosage form (IR/XR mixed particles). The IR particles        provide the initial release of the therapeutic agent followed by        extended release from the XR particles (IR/XR mixed population        of particles).    -   A single population of particles in a capsule, compressed tablet        or any other dosage form where the particles are either matrix        XR particles, or IR cores further comprising an XR coating.    -   Mixed particles in a capsule, compressed tablet or any other        dosage form where XR particles of differing drug release        characteristics are combined.    -   Mixed particles in a capsule, compressed tablet or any other        dosage form where DR particles of differing drug release        characteristics are combined, optionally resulting in a        pulsatile profile.    -   Mixed particles in a capsule, compressed tablet or any other        dosage form where IR particles are mixed with DR particles        (IR/DR mixed particles). The IR particles provide the initial        release of the therapeutic agent followed by release from the DR        particles resulting in pulsed PK profiles. (IR/DR mixed        population of particles)    -   A single population of particles in a capsule, compressed tablet        or any other dosage form where the pellet incorporates an IR        core coated with DR coat, which is further coated with an IR        drug layer. The outer IR drug layer provides an immediate        release of the therapeutic agent followed by a delayed release        from the DR core resulting in pulsed PK profile. (IR/DR single        population of particles)    -   Mixed particles in a capsule, compressed tablet or any other        dosage form where IR particles are mixed with DR coated XR        particles (IR/DR-XR). The IR particles provide the initial        release of the therapeutic agent followed by delayed and        extended release from the DR coated XR particles. (IR/DR-XR        mixed population of particles)    -   A single population of particles in a capsule, compressed tablet        or any other dosage form where the pellet incorporates an IR        core coated with XR coat, which is coated with DR coat that is        subsequently drug layered. The outer drug layer provides the        initial immediate release of the therapeutic agent followed by        delayed and extended release from the remainder of the pellet.        (IR/DR-XR single population of particles)    -   Mixed particles in a capsule, compressed tablet or any other        dosage form where XR particles are mixed with DR particles. The        XR provides the initial and continuing release of the        therapeutic agent followed by release from the DR particles.        (XR/DR mixed population of particles)    -   A single population of particles in a capsule, compressed tablet        or any other dosage form where the pellet incorporates IR core        coated with a DR coat which is then coated with a drug layer        that is subsequently coated with an XR coat to produce a fast XR        layer. The fast XR outer layer provides the initial release of        the therapeutic agent followed by delayed release from the DR        core. (XR-f/DR single population of particles).    -   An XR tablet, which is either a matrix tablet or an XR-coated        tablet.    -   A DR tablet coated with an IR drug layer.    -   One or more than one DR tablets mixed with one or more IR        tablets in a capsule.    -   XR tablet coated with a DR coat, then coated with an IR drug        layer.    -   A bi-layer tablet with one layer containing the drug in XR form        and a 2^(nd) layer containing the drug in an IR form.    -   A bi-layer tablet with one layer containing the drug in XR form        and a 2^(nd) layer containing the drug in DR form.    -   A DR coated matrix tablet providing a DR/XR profile.

(C) Osmotic release systems. In a further embodiment, the inventionprovides an extended release viloxazine preparation in the form of anosmotic tablet, wherein the drug release rate is determined by the rateof water permeation into the tablet core through a semi-permeablemembrane coating.

For the preparation of an osmotic tablet, viloxazine may be mixed withosmotic agent(s), tableting aides such as diluents and lubricants, andother commonly used excipients. The mixture is tableted either by directcompression or granulation followed by compression. Tablets are thencoated with at least one release rate controlling compound that forms asemi-permeable membrane that surrounds each tablet.

The semipermeable membrane, which surrounds the drug-containing core,comprises at least one release rate controlling compound selected fromfollowing cellulose esters, cellulose ethers and cellulose ester ethers.Non-limiting examples of such compounds include cellulose acylate,cellulose ethyl ether, cellulose diacylate, cellulose triacylate,cellulose acetate, cellulose diacetate, cellulose triacetate, mono-, di-and tricellulose alkyls, mono-, di- and tricellulose aroyls, and thecombinations thereof. Additional release rate controlling compoundsinclude ethyl cellulose, EUDRAGIT® RS and EUDRAGIT® RL (poly(ethylacrylate-co-methyl methacrylate-cotrimethylammonioethyl methacrylatechloride), and EUDRAGIT® NE 30 D or EUDRAGIT® NM 30 D poly(ethylacrylate-co-methyl methacrylate), ethyl acrylate methyl methacrylatecopolymer.

The semi-permeable membrane may be applied on the tablets using standardcoating techniques such as spraying, dipping, casting, coating solventevaporation, molding or compression coating. An orifice is then drilledin the tablet coat using laser tablet drilling system or othermechanical means to allow the release of drug from the core.

Osmotic agents used for the practice of the current invention are wellknown in the art and include non-swellable compounds represented by, butnot limited to polyols, carbohydrates (including monosaccharides,oligosaccharides, polysaccharides and sugar alcohols), acids, salts andhydrophilic compounds. For example, osmotic agents may be selected frommannitol, maltrin, xylitol, maltitol, lactitol, isomalt, sorbitol,arabitol, erythritol, ribitol, insositol, trehalose, lactose, glucose,sucrose, raffinose, fructose, dextran, glycine, urea, citric acid,tartaric acid, ascorbic acid, aspartame, malic acid, sodium chloride,potassium chloride, magnesium chloride, disodium hydrogen phosphate,sodium phosphate, potassium phosphate, sodium sulfate, lithium sulfate,magnesium sulfate, magnesium succinate, sodium bicarbonate, sodiumcarbonate, sodium acetate, sodium ascorbate, polyethylene glycol,maltodextrin, cyclodextrins and derivatives, non-swelling block polymersof PEO and PPO, polyethylene glycols, cellulose ethers, and combinationsthereof.

Osmotic tablets can be formulated as a single or as a multiple layercore. In one embodiment, the osmotic tablet comprises a bilayer core,wherein one layer comprises agents to modulate drug release, such as asolubilizer, that are released in an extended manner, and the secondlayer comprises the drug and potentially other agents to modulate drugrelease.

An overcoat of drug can be applied to the tablet following functionalcoating to provide an immediate release component to the dosage form.Alternatively, the osmotic tablet may be coated with an enteric compoundon top of the semipermeable membrane providing a DR/XR profile.

In addition to the release rate controlling compounds, a number ofpharmaceutically acceptable excipients may be used in the formulationsof the invention as disclosed above. These excipients are well known inthe art, and include binders and diluents, such as povidone, starch,gelatin, maltodextrin, methylcellulose, hydroxypropyl cellulose,hydroxypropyl methylcellulose, carboxymethylcellulose, sucrose,dextrose, acacia, tragacanth and locust bean gum, microcrystallinecellulose, dicalcium phosphate, calcium sulfate, cellulose, and talc;lubricants such as sodium stearyl fumarate and the metallic stearatessuch as magnesium stearate; wetting and solubilizing agents such assodium docusate, sodium lauryl sulfate, polyethylene glycol, lecithin,poloxamer, polysorbates, polyoxyethylene ethers and sorbitan esters;disintegrants such as crosslinked sodium carboxymethylcellulose, sodiumstarch glycolate and crospovidone; buffering agents and/or pH modulatingagents, such as aluminum hydroxide, ammonium bicarbonate, ammoniumcarbonate, ammonium phosphate, arginine, calcium acetate, calciumascorbate, magnesium acetate, magnesium carbonate, potassium acetate,potassium bicarbonate, potassium carbonate, potassium phosphate dibasic,potassium sodium tartrate, potassium citrate, sodium citrate, sodiumphosphate monobasic, sodium phosphate dibasic, sodium phosphatetribasic, sodium acetate, sodium bicarbonate, sodium ascorbate, sodiumcarbonate, fumaric acid, malic acid, tartaric acid, ascorbic acid,aspartic acid, alginic acid, glutamic acid, sorbic acid, and succinicacid; and glidants such as talc, starch and colloidal silicon dioxide;pore formers modulating the permeability of the semipermeable ratecontrolling membrane such as povidone, hypromellose, hydroxyethylcellulose, hydroxypropyl cellulose, organic acids and salts amongstother excipients.

(D) Gastro-retentive systems. In a further embodiment, the inventionprovides an extended release viloxazine preparation in the form of agastro-retentive tablet, in particular a gastro-retentive extendedrelease tablet. The gastro-retentive tablet is designed to be retainedin the stomach for up to 6 hours after ingestion, after which theremaining dosage form and essentially all undissolved drug is releasedinto the duodenum to transit through the gastrointestinal tract. Thein-vitro dissolution profile used for the GR-ER tablet releases 80% ofthe dose of drug contained in the dosage form in approximately 10 hours.

Formulations of the instant invention are characterized by a lowerincidence of gastrointestinal side effects such as dyspepsia, nausea andvomiting and neurological side effects including sleep disturbances suchas insomnia and abnormal dreams.

It was further unexpectedly discovered during the development of theinventive formulations that the water solubility and dissolution rate ofa viloxazine salt may be influenced by the addition of a common ion intothe formulation. For example, the dissolution rate and solubility ofviloxazine hydrochloride is influenced by the addition of chloridecontaining substances such as sodium chloride, potassium chloride,calcium chloride or magnesium chloride, or other chloride salts (Example12).

Another aspect of the present invention is the treatment of CNSdisorders in mammalian subjects, including but not limited to thetreatment of ADHD, ADHD related disorders and depressive disorders, withmodified release formulations of viloxazine as described herein. Onetreatment regimen comprises administering the viloxazine formulation ofthe current invention to a subject once or twice a day to provide atotal daily dose ranging from 10 mg to 800 mg of viloxazine (base).

In an additional embodiment, the invention also discloses formulationsof viloxazine that can provide therapeutic levels of the drug for theperiod of time from 4 to 24 hours, or for the periods of from 8 to 20hours, or for the periods of from 12 to 16 hours.

Formulations of the instant invention are characterized by a maximumsteady state plasma concentration (C_(max)) of viloxazine which ishigher than the minimal therapeutically effective concentration and isin the range of 50% to 125% relative to the maximum plasma concentrationproduced by the administration of from 100 mg to 600 mg, in particular,of from 150 mg to 300 mg, of from 300 mg to 450 mg, of from 450 mg to600 mg of viloxazine as an IR formulation three times daily (TID) ortwice daily (BID). In one embodiment, the novel formulations provide fora relative C_(max) in the range of 80% to 125%, as compared toviloxazine administered as an IR formulation TID or BID. In the otherembodiment, the invention provides for the C_(max) which is lower thanthe maximum plasma concentration produced by viloxazine administered asan IR formulation TID or BID.

Further, the formulations of the instant invention are characterized bya maximum steady state plasma concentration (C_(max)) of viloxazine inthe range of from 1.5 μg/mL to 11 μg/mL, in particular in the range offrom 1.5 μg/mL to 3 μg/mL, or of from 3 μg/mL to 6 μg/mL; or of from 6μg/mL to 9 μg/mL, or from 9 μg/mL to 11 μg/mL.

The formulations of the current invention also provide relative steadystate area under the viloxazine plasma concentration—time profiles for a24 hour dosing interval (AUC_(tau)) in the range of 80% to 125% ascompared to viloxazine administered as an IR formulation TID or BID.Further, the formulations of the instant invention are characterized byAUC_(tau) in the range of 80% to 125%, of the AUC achieved by theselected IR dosing scheme.

Additionally, the present invention provides extended release dosageforms that overcome the surprising lower mean relative bioavailabilityobserved in a clinical pilot PK study in healthy human subjects of theextended release formulations of Example 15 as compared to the immediaterelease formulation dosed in the study. This effect was accomplished byconstructing the extended release dosage forms by the careful selectionof viloxazine dose to be delivered and the in vitro dissolution profileof the extended release dosage form such that the relative viloxazinesystemic in vivo exposure achieved at steady state for the extendedrelease dosage form, as measured by the viloxazine plasmaconcentration-time profile for a 24 hour dosing interval (AUC_(tau)), is80% to 125% of that achieved by viloxazine dosed as immediate releaseformulation three times daily (TID) or twice daily (BID).

In a further embodiment, the invention discloses a method of treatmentof the CNS disorders such as listed above with high-drug loadformulations of viloxazine exhibiting modified release. Theseformulations are characterized by the amount of viloxazine in thefinished drug product from about 25% w/w to about 75% w/w, or from about30% (w/w) to about 60% (w/w), or from about 40% (w/w) to about 50%(w/w).

The method results in the reduced frequency of administration and in thediminishing number of units that should be taken by the patient, andthus in better compliance and treatment outcomes.

The invention is further illustrated by, though in no way limited to,the following examples.

Examples Example 1 Extended Release Matrix Tablet of Viloxazine(PD0348-005)

The manufacturing process for the matrix tablet included preparation ofa wet granulation (Glatt table top granulator—1 L bowl) of viloxazinehydrochloride, hypromellose (METHOCEL™ K15M) and microcrystallinecellulose (Avicel® PH101) using a solution of a low molecular weighthypromellose (METHOCEL™ E5) and water as the granulating medium. The wetgranulation was oven dried at 40° C. to a moisture level of less than 1%(w/w) and then sized by passing through an 18 mesh sieve. The sievedmaterial was then blended with additional microcrystalline cellulose(Avicel® PH 102), colloidal silicon dioxide, NF, talc, USP and magnesiumstearate, NF producing the final tablet blend formulation PD0348-005(Table 1). The final tablet blend was compressed into extended-releasetablets at the dose strengths of 50 mg and 200 mg (as viloxazine base).

TABLE 1 Formulation PD0348-005 Usage Compressed Tablet^(a) (% w/w)Viloxazine Hydrochloride 34.60 METHOCEL ™ K15M Premium CR 31.59 Avicel ®PH 101 14.24 Avicel ® PH 102 12.53 METHOCEL ™ E5 Premium LV 2.04 Talc,USP 3.00 Colloidal Silicon Dioxide, NF 1.00 Magnesium Stearate, NF 1.00Total 100 ^(a)Drug load 35% (w/w) viloxazine hydrochloride

The 200 mg dose strength tablet formulation was evaluated fordissolution (FIG. 1). These compressed tablets exhibited consistentcontent uniformity. The dissolution profile of PD0348-005 was pHindependent, exhibiting extended-release with a t₈₀ (time to release 80%label claim) of 14 hours.

Example 2 Effect of the Higher Drug Loads on the Drug Release

Tablet PD0348-005 was reformulated to study the effect of higher drugloads on the drug release from the matrix. The content of viloxazinehydrochloride was increased to 40% (w/w) in formulation PD0348-069 and45% (w/w) in formulation PD0348-071 while reducing the amount of Avicel®but maintaining the same amount of METHOCEL™ K15M. These tablets weremanufactured in a similar manner as PD0348-005.

TABLE 2 Formulation PD0348-069 (200 mg dose strength) Usage CompressedTablet^(a) (% w/w) Viloxazine Hydrochloride 40.00 METHOCEL ™ K15MPremium CR 30.00 Avicel ® PH 101 23.00 METHOCEL ™ E5 Premium LV 3.00Talc, USP 3.00 Magnesium Stearate, NF 1.00 Total 100 ^(a)Drug load 40%(w/w) viloxazine hydrochloride

TABLE 3 Formulation PD0348-071 (200 mg dose strength) Usage CompressedTablet^(a) (% w/w) Viloxazine Hydrochloride 44.99 METHOCEL ™ K15MPremium CR 30.00 Avicel ® PH 101 18.00 METHOCEL ™ E5 Premium LV 3.00Talc, USP 3.00 Magnesium Stearate, NF 1.00 Total 100 ^(a)Drug load 45%(w/w) viloxazine hydrochloride

Formulations PD0348-069 and PD0348-071 were subjected to dissolutiontesting (n=3) at pH 6.8 and the profiles (FIG. 2) were compared toPD0348-005 using the similarity factor test (f₂) using the followingequation (Guidance for Industry SUPAC-MR: Modifies Release Solid OralDosage Forms, CDER September 1997):

f ₁=50 log {[1+1/nΣ _(t=1) ^(n)(R _(t) −T _(t))²]^(−0.5)×100}

Wherein: n is the number of time points (n=8)

-   -   R is the reference formulation (PD0348-005); and    -   T is the test formulation (PD0348-069 or PD0348-071)

The f₂ values calculated for PD0348-069 and PD0348-071 were 74 and 67,respectively. An f₂ value between 50 and 100 suggests that thedissolution profile of the test formulation is similar to that of thereference formulation.

Additional matrix tablet dose strengths are possible, for examplePD0348-071 can be compressed into reasonable sized tablets for dosestrengths of 100 mg, 300 mg, 400 mg or 600 mg.

Example 3 Dissolution Testing of the Matrix Tablet

TABLE 4 Formulation PD0348-015 Usage Compressed Tablet^(a) (% w/w)Viloxazine Hydrochloride 34.60 POLYOX ™ WSR 303 30.00 Avicel ® PH 10121.62 Avicel ® PH 102 5.03 METHOCEL ™ E5 Premium LV 3.75 Talc, USP 3.00Colloidal Silicon Dioxide, NF 1.00 Magnesium Stearate, NF 1.00 Total 100^(a)Drug load 35% (w/w) viloxazine hydrochlorideThe manufacture of the final tablet blend for PD0348-015 was similar tothat of PD0348-005. PD0348-015 was compressed into 50 mg and 200 mg dosestrength tablets. The 200 mg dose strength tablet was evaluated for drugrelease by dissolution testing (n=3) at both pH 1.1 and pH 6.8 (FIG. 3).The dissolution profile of PD0348-015 was pH independent exhibitingextended-release with a t₈₀ of 14 hours.

Example 4 Extended Release Matrix Tablet of Viloxazine (PD0348-041)

TABLE 5 Formulation PD0348-041 (200 mg dose strength) Compressed TabletUsage (% w/w) Viloxazine Hydrochloride 34.60 EUDRAGIT ® NE 30 D (solids)12.04 METHOCEL ™ K15M Premium CR 19.55 Avicel ® PH 101 14.24 Avicel ® PH102 12.52 METHOCEL ™ E5 Premium LV 2.04 Talc, USP 3.00 Colloidal SiliconDioxide, NF 1.00 Magnesium Stearate, NF 1.00 Total 100

The manufacturing process for PD0348-041 differed from PD0348-005 inthat the METHOCEL™ E5 was dry blended with the viloxazine hydrochloride,hypromellose (METHOCEL™ K15M) and microcrystalline cellulose (Avicel®PH101) and the EUDRAGIT® NE 30 was sprayed as the granulating fluid.

Formulation PD0348-041 was evaluated for drug release by dissolutiontesting (n=3) at both pH 1.1 and pH 6.8 (FIG. 4). The dissolutionprofile of PD0348-041 exhibited extended-release with a t₈₀ ofapproximately 14 hours.

Example 5 Pellets of Viloxazine (PD0348-108: PD0348-114A)

Pellets were manufactured using an extrusion/spheronization process toproduce high drug load pellets. Initially, a wet granulation wasproduced (Glatt VG-10 L bowl) comprising viloxazine hydrochloride,microcrystalline cellulose (Avicel® PH101), isomalt (galenlQ™ 810) andtalc using a solution of METHOCEL™ E5 in water as the granulatingmedium. Table 6 provides the granulation formulation.

TABLE 6 Granulation Formulation PD0348-099 Component Usage (% w/w)Viloxazine Hydrochloride 75.00 Avicel ® PH 101 13.75 galenIQ 810 5.25METHOCEL ™ E5 Premium LV 3.00 Talc, USP 3.00 Total 100

The resulting granulation was extruded using a LCI-Fuji Paudal DomeGranulator (Model DG-L2 equipped with a 0.7ϕ/1.0T screen) and thenspheronized using a LCI-Fuji Paudal Marumerizer (Model QJ-400G) toproduce IR pellets. The pellets were then oven dried over night at 45°C. The dried pellets were screened (stacked sieves 18 mesh over 40 mesh)and then seal coated using a Wurster process (GPCG-1) to 5% weight gainwith Opadry® II White (33G28523) (PVA-based coating system). The sealcoated IR pellets, lot PD0348-108, were evaluated for dissolution at pH1.1 (Table 7). Complete dissolution was observed within 15 minutes.

TABLE 7 Dissolution of 200 mg Dose Strength IR Pellet Lot PD0348-108 atpH 1.1^(a) Time (minutes) Percent Released ^(b) 15 98 30 98 45 98 60 98120 98 ^(a)Dissolution conditions: USP II at 50 RPM, 900 mL pH 1.1 0.1Nhydrochloric acid at 37° C. (±0.5° C.), ^(b) Mean of three vessels

The seal coated IR pellets were coated with Surelease® E-7-19010 using aWurster process (GPCG-1) to a weight gain of 10% (w/w) resulting inviloxazine hydrochloride content in the coated pellets of 64% (w/w) lotPD0348-114A. The coated pellets were oven cured for 72 hours at 50° C.and then evaluated for drug release (FIG. 5). The release profileexhibits near zero order release over the interval of 2 hours to 20hours (R² value of 0.997 by linear regression analysis) with a t₈₀ of 24hours. PD0348-114A is an example of a pellet composition exhibiting aslow in vitro release profile that can be combined with one or morepellet compositions having faster release profiles.

Example 6 Multiparticulates of Viloxazine (PD0354-004C)

The granulation formulation (PD0348-134A/B) used to produce the IRpellets for the extended-release pellet lot PD0354-004C is presented inTable 8.

TABLE 8 Granulation Formulation PD0348-134A/B Component Usage (% w/w)Viloxazine Hydrochloride 65.00 Avicel ® PH 101 30.00 METHOCEL ™ E5Premium LV 1.50 Povidone, USP (K-value 30) 1.00 Talc, USP 2.50 Total 100

The granulation process for PD0348-134A/B was similar to PD0348-099 withan additional step in that the Povidone, USP was dissolved in thegranulating water along with the METHOCEL™ E5. The granulation wasextruded on the Model DG-L2 dome granulator equipped with a 0.61)/0.6Tscreen and then spheronized on the Model QJ-400G Marumerizer. Thespheronized product was oven dried for 24 hours at 45° C. The driedpellets were screened (stacked 20 mesh over 40 mesh sieves) and thenseal coated using a Wurster process (GPCG-1) to 5% weight gain withOpadry® II White (33G28523). Following application of the seal coat thepellets were coated with EUDRAGIT® NE 30 D containing Povidone, USP (ata ratio of 9:1 EUDRAGIT® NE 30 D solids to Povidone, USP solids) to aweight gain of 14% (w/w), oven cured for 24 hours at 45° C. and thenscreened (stacked 20 mesh over 40 mesh sieves). The screened pelletswere then coated on the GPCG-1 with Surelease® E-7-19010 to a weightgain of 9% (w/w) resulting in a final viloxazine hydrochloride contentof 42% (w/w). The coated pellets were oven cured for 24 hours at 50° C.and then evaluated for drug release (FIG. 6). The release profileexhibits a lag of 1-2 hours and then near zero order release over theinterval of 4 hours to 14 hours (R² value of 0.990 by linear regressionanalysis) with a t₈₀ of 12 hours.

Examples 7, 8 and 9 Extended Release Pellet Formulations

A series of extended-release pellet formulations were prepared coatingseal coated IR pellets (formulation of Example 6) with Surelease®E-7-19010 containing the pore former, METHOCEL™ E5 Premium LV (E5) todemonstrate the range of extended release profiles that can be achievedwith the pellet compositions. The ratios (Surelease® to E5) studiedincluded 19:1, 9:1 and 8.5:1.5. Representative drug release profiles forthese systems are presented in FIG. 7 (19:1) for 8% (w/w) and 13% (w/w)coating, FIG. 8 (9:1) for 5% (w/w), 7.5% (w/w) and 10% (w/w) coating,and FIG. 9 (8.5:1.5) for 14% (w/w) and 18% (w/w) coating.

Example 10 Influence of Particle Size on the Drug Release

Studies were conducted to evaluate the drug release from pellets ofdifferent particle size fractions, isolated by sieve sizing, after theextended release coating process for lot PD0377-006B. The extendedrelease pellet lot PD0377-006B was prepared by coating seal coated IRpellets (formulation of Example 6) with Surelease® E-7-19010 containingthe pore former, METHOCEL™ E5 Premium LV at the ratio of 9:1 to a levelof 12% (w/w). The pellet lot was segregated into different sizefractions using the following stacked configurations of hand sieves: 18mesh over 20 mesh, 20 mesh over 25 mesh, and 25 mesh over 30 mesh.Samples of these fractions were evaluated for drug release at pH 6.8(FIG. 10). The profiles in FIG. 10 illustrate that the size of the IRpellet can be utilized as a controlling parameter for the drug releaseprofile of the pellet formulation. Also, the plots indicate that controlof the size distribution of the IR pellets is needed for a robustextended release coating process. The size range for the IR pellets ofthis invention is 5 mesh (4000 μm) to 200 mesh (75 μm). Ideally thepellet size range is 10 mesh (2000 μm) to 100 mesh (150 μm).

Example 11 Preparation of the Encapsulated Pellets (PD0380-191,PD0380-192 and PD0383-035

Two extended release pellet lots were prepared by coating seal coated IRpellets (formulation of Example 6) with Surelease® E-7-19040 containingthe pore former, METHOCEL™ E5 Premium LV at the ratio of 9:1 to a levelof 10% (w/w). Extended-release pellet lot PD0380-147B was prepared usingseal coated IR pellets of the size fraction between that of a 20 meshsieve and a 25 mesh sieve. Extended-release pellet lot PD0383-009C wasprepared using seal coated IR pellets of the size fraction between thatof a 16 mesh sieve and a 20 mesh sieve. The extended-release pellet lotswere encapsulated in size 0, white, opaque, hard gelatin capsules at thedose strength of 150 mg viloxazine base; extended-release capsule lotPD0380-191 contained 100% pellet lot PD0380-147B, extended-releasecapsule lot PD0380-192 contained 100% pellet lot PD0383-009C andextended-release capsule lot PD0383-035 was a mixture of 50% each lotPD0380-147B and lot PD0383-009C. The encapsulated drug products wereevaluated for drug release at pH 6.8 (FIG. 11).

Example 12 Influence of the Chloride Ion on the Solubility of ViloxazineHydrochloride

It was experimentally determined that the water solubility of viloxazinehydrochloride at room temperature and at 37° C. decreased significantlyas a function of sodium chloride concentration (FIG. 12). The reason forthe decrease in viloxazine hydrochloride solubility was believed to be acommon ion effect of chloride. This effect was further evaluated byadding two chloride ion sources (NaCl and KCl) to pH 6.8 phosphatebuffer and evaluating the drug release of pellet formulation PD0354-076Cat the dose of 200 mg viloxazine base (231 mg viloxazine hydrochloride)(FIG. 13). The drug release rate was suppressed in both of the mediacontaining the added chloride salts.

Example 13 IR Capsule Formulations of Viloxazine for Clinical Studies

IR capsule formulations of viloxazine developed for use in Phase I andPhase IIa clinical studies (Table 9 and Table 10).

TABLE 9 Viloxazine Capsules, 50 mg (viloxazine base) Component QuantityPer Dosage Unit (g) Viloxazine Hydrochloride ^(a) 57.68 MicrocrystallineCellulose, NF 227.84 Magnesium Stearate, NF 2.88 Hard Gelatin Capsule,Size 0 ^(b) 96.0 Total 384.40 ^(a) Equivalent to 50 mg viloxazine base.^(b) Target empty capsule shell weight based on the productspecification.

TABLE 10 Viloxazine Capsules, 100 mg (viloxazine base) ComponentQuantity Per Dosage Unit (g) Viloxazine Hydrochloride ^(a) 115.36Microcrystalline Cellulose, NF 170.16 Magnesium Stearate, NF 2.88 HardGelatin Capsule, Size 0 ^(b) 96.0 Total 384.40 ^(a) Equivalent to 50 mgviloxazine base. ^(b) Target empty capsule shell weight based on theproduct specification.

Example 14 Extended Release Capsule Formulations of Viloxazine forClinical Studies

Three extended-release capsule formulations of viloxazine formulated todeliver 150 mg of viloxazine base were developed for a Phase I PK studyin healthy subjects. The drug products were formulated to providedifferent in vitro extended drug release profiles (i.e., fast extendedrelease formulation designated ER-1, medium extended release formulationdesignated ER-2 and slow extended release formulation designated ER-3).In addition, an immediate-release capsule formulation containing 150 mgof viloxazine base was developed for the clinical study as a comparatordrug product.

The manufacture of the extended release drug products started with a wetgranulation that was produced utilizing a high-shear granulationprocess. The wet granulation was extruded and spheronized to formpellets that were subsequently dried by fluid bed resulting inviloxazine nIR pellets (Table 11).

TABLE 11 Viloxazine nIR Pellets (56.36% (w/w) as viloxazine base)Component Quantity Per Batch (g) Viloxazine Hydrochloride 3120.0Microcrystalline Cellulose, NF 1440.0 Talc, USP 120.0 Hypromellose, USP^(a) 72.0 Povidone, USP ^(b) 48.0 Sterile Water for Irrigation, USP ^(c)1728.0 Total 4800 ^(a) Type 2910 ^(b) K-value 30 ^(c) Removed duringprocessing

Following drying, the Viloxazine nIR Pellets were screened to producethree specific pellet size ranges based on sieve mesh size: a 25 mesh/35mesh cut, a 20 mesh/25 mesh cut and a 16 mesh/20 mesh cut. Theindividual mesh cut Viloxazine nIR Pellets were film coated (Opadry® IIWhite) using a fluid bed producing Viloxazine sIR immediate-releasepellets (Viloxazine sIR 2525, Viloxazine sIR 2025 and Viloxazine sIR1620 pellets). The three Viloxazine sIR Pellet products were used in theproduction of four extended-release bulk pellets formulations(Viloxazine ER-S Pellets, Viloxazine ER-F Pellets, Viloxazine ER-F2Pellets and Viloxazine ER-F3 Pellets) by coating the Viloxazine sIRPellets with an extended-release coating system comprising Surelease®E-7-19040, Hypromellose, USP and Sterile Water for Injection, USP usinga fluid bed. The compositions for the four extended release bulk pelletsformulations are provided in Tables 12-15.

TABLE 12 Viloxazine ER-S Pellets (47.24% (w/w) as viloxazine base)Component Quantity Per Batch (g) Viloxazine sIR1620 Pellets 1852.9Surelease ® E-7-19040 ^(a, b) 741.2 Hypromellose, USP ^(c) 20.6 Talc,USP 41.2 Sterile Water for Irrigation, USP ^(d) 1166.7 ComponentQuantity Per Batch (g) Total 2100 ^(a) Product number E-7-19040 ^(b) Thequantity for Surelease ® Clear reports the usage of the aqueous coatingdispersion. ^(c) Type 2910 ^(d) Removed during processing

TABLE 13 Viloxazine ER-F Pellets (47.24% (w/w) as viloxazine base)Component Quantity Per Batch (g) Viloxazine sIR2025 Pellets 1852.9Surelease ® E-7-19040 ^(a, b) 741.2 Hypromellose, USP ^(c) 20.6 Talc,USP 41.2 Sterile Water for Irrigation, USP ^(d) 1166.7 Total 2100 ^(a)Product number E-7-19040 ^(b) The quantity for Surelease ® Clear reportsthe usage of the aqueous coating dispersion. ^(c) Type 2910 ^(d) Removedduring processing

TABLE 14 Viloxazine ER-F2 Pellets (47.24% (w/w) as viloxazine base)Component Quantity Per Batch (g) Viloxazine sIR2535 Pellets 1852.9Surelease ® E-7-19040 ^(a, b) 741.2 Hypromellose, USP ^(c) 20.6 Talc,USP 41.2 Sterile Water for Irrigation, USP ^(d) 1166.7 Total 2100 ^(a)Product number E-7-19040 ^(b) The quantity for Surelease ® Clear reportsthe usage of the aqueous coating dispersion. ^(c) Type 2910 ^(d) Removedduring processing

TABLE 15 Viloxazine ER-F3 Pellets (47.24% (w/w) as viloxazine base)Component Quantity Per Batch (g) SPN-812V sIR2535 Pellets (53.54% w/w)1852.9 Surelease ® E-7-19040 ^(a, b) 741.2 Hypromellose, USP ^(c) 20.6Talc, USP 41.2 Sterile Water for Irrigation, USP ^(d) 1166.7 Total 2100^(a) Product number E-7-19040 ^(b) The quantity for Surelease ® Clearreports the usage of the aqueous coating dispersion. ^(c) Type 2910 ^(d)Removed during processing

Viloxazine sIR2535 Pellets were encapsulated into size 0 white opaquehard gelatin capsules at the dose strength of 150 mg viloxazine base toproduce the immediate-release comparator drug product (batch B11016A).Viloxazine ER-F2 Pellets and Viloxazine ER-F3 Pellets were encapsulated,at the ratio of 1:1, into size 0 white opaque hard gelatin capsules atthe dose strength of 150 mg viloxazine base to produce Viloxazine ER-1capsules (batch B11030A). Viloxazine ER-F Pellets were encapsulated intosize 0 white opaque hard gelatin capsules at the dose strength of 150 mgviloxazine base to produce Viloxazine ER-2 capsules (batch B11028A).Viloxazine ER-S Pellets were encapsulated into size 0 white opaque hardgelatin capsules at the dose strength of 150 mg viloxazine base toproduce Viloxazine ER-3 capsules (batch B11026A). The encapsulated drugproducts were evaluated for drug release at pH 6.8 (FIG. 14).

The pharmacokinetic profile of the three extended-release viloxazinecapsule formulations ER-1, ER-2 and ER-3 and the immediate-releasecapsule formulation was studied in a single dose (150 mg viloxazinebase), four treatments, four sequences, crossover study in healthy adultvolunteers. Twenty-one subjects completed all four treatment arms. Themean PK profiles from this study are provided in FIG. 15.

Example 15 Pharmacokinetic Analysis of Extended Release Formulations

Non-Compartmental pharmacokinetic analysis was conducted on the meanplasma profiles of Example 14 using WinNonlin Professional version 5.3(WinNonlin® Copyright © 1998-2009, Tripos L.P.) to determine the percentbioavailability of the three extended-release formulations (ER-1, ER-2and ER-3) dosed at 150 mg viloxazine base relative to that achieved withthe immediate-release capsule formulation also dosed at 150 mgviloxazine base. The percent relative bioavailability values determinedwere 78% for ER-1, 68% for ER-2 and 57% for ER-3. The relativebioavailability values for the three extended-release formulations weresurprising low. The trend in the relative bioavailability valuessuggests that the absorption of viloxazine is reduced in the distalregions of the gastrointestinal tract and that composite formulationcomprising several components with different profiles may beadvantageous for maximizing bioavailability.

Example 16 Plasma Profiles of the R- and S-Formulations

The plasma samples obtained for the extended-release formulation ER-2and the IR capsule formulation of Example 14 were evaluated using abioanalytical method capable of separating R-viloxazine andS-viloxazine. The mean plasma profiles for the individual isomers forthe IR capsule formulation are provided in FIG. 16 and the mean plasmaprofiles for the individual isomers for ER-2 are presented in FIG. 17.The R to S isomer ratio in the actual drug products as well as the drugsubstance lot used to manufacture the drug products was determined to be50:50. Surprisingly, the R to S isomer ratio of the mean plasma profilesdiffered when comparing the IR capsule formulation (70:30) to that ofER-2 (60:40). This finding suggests that R and S isomers may bemetabolized differently from the IR and ER formulations and thatpreferential metabolism of one of the isomers may be induced throughstrategically developed formulations.

Example 17 In Silico Modeling of the Steady State Viloxazine Systemic InVivo Exposure (ER1, ER2 and ER3

In silico modeling was conducted using GastroPlus™ (copyright 2001-2010Simulations Plus Inc.) and the mean drug release and plasmaconcentration profiles of Example 14 to develop simulated plasmaconcentration profiles for extended-release formulation conceptsexhibiting steady state viloxazine systemic in vivo exposure similar tothat of immediate-release formulation dosing schemes. All formulationdoses used were as viloxazine base.

-   (a) FIG. 18 presents the comparison of the steady state simulated    plasma profiles for an immediate-release 50 mg viloxazine dosage    form dosed every 8 hours (TID) to that of two extended-release    viloxazine formulation compositions dosed once daily (qd). The first    extended release composition contains 250 mg of ER-3 pellets and the    second extended release composition contains 30 mg IR pellets and    200 mg of ER-3 pellets. Pharmacokinetic analysis of the simulated    profiles for a dosing cycle of 24 hours (AUC_(tau)) estimated that    the systemic in vivo exposure for the extended-release composition    of 250 mg ER-3 pellets would be 86% and that for the composition of    30 mg IR pellets and 200 mg of ER-3 pellets would be 89% of the    systemic exposure achieved with this particular IR dosing scheme.-   (b) FIG. 19 presents the comparison of the steady state simulated    plasma profiles for an immediate-release 75 mg viloxazine dosage    form dosed twice daily (BID) with the first dose given at 8 AM and    the second dose given 8 hours later (at 4 PM) to that of two    extended-release viloxazine formulation compositions dosed qd. The    first extended release composition contains 180 mg of ER-1 pellets    and the second extended release composition contains 30 mg IR    pellets and 150 mg of ER-1 pellets. Pharmacokinetic analysis of the    simulated profiles for a dosing cycle of 24 hours (AUC_(tau))    estimated that the systemic in vivo exposure for the    extended-release composition of 180 mg ER-1 pellets would be 93% and    that for the composition of 30 mg IR pellets and 150 mg of ER-1    pellets would be 98% of the systemic exposure achieved with this IR    dosing scheme. FIG. 20 presents the same extended-release    compositions however, compared to an IR BID dosing scheme with the    first dose given at 6 AM and the second dose given at 4 PM (10 hours    later). The first extended release composition contains 180 mg of    ER-1 pellets and the second extended release composition contains 30    mg IR pellets and 150 mg of ER-1 pellets.-   (c) FIG. 21 presents the comparison of the steady state simulated    plasma profiles for an immediate-release 75 mg viloxazine dosage    form dosed twice daily (BID) with the first dose given at 8 AM and    the second dose given 8 hours later (at 4 PM) to that of two    extended-release viloxazine formulation compositions dosed qd. The    first extended release composition contains 90 mg of ER-1 pellets    and 90 mg of ER-2 pellets. The second extended release composition    contains 20 mg IR pellets, 90 mg of ER-1 pellets and 90 mg of ER-2    pellets. Pharmacokinetic analysis of the simulated profiles for a    dosing cycle of 24 hours (AUC_(tau)) estimated that the systemic in    vivo exposure for the extended-release composition of 90 mg of ER-1    pellets and 90 mg of ER-2 pellets would be 85% and that for the    composition of 20 mg immediate-release pellets, 90 mg of ER-1    pellets and 90 mg of ER-2 pellets would be 98% of the systemic    exposure achieved with this IR dosing scheme.

Example 18 In Silico Modeling of the Steady State Viloxazine Systemic InVivo Exposure of ER Capsule Composition

In silico modeling was conducted using GastroPlus™ (copyright 2001-2010Simulations Plus Inc.) to develop a simulated plasma concentrationprofile for a three pellet extended release capsule composition concept.All formulation doses used were as viloxazine base.

FIG. 22 presents the comparison of the steady state simulated plasmaprofiles for an immediate-release 50 mg viloxazine dosage form dosedevery 8 hours (TID) to that of an extended-release viloxazineformulation composition dosed qd. The ER composition contains 25 mg IRpellets, 75 mg of DR2-ER-1 pellets (a hypothetical composition ofdelayed-release of ER1 pellets) and 90 mg of ER-2 pellets.Pharmacokinetic analysis of the simulated profile for a dosing cycle of24 hours (AUC_(tau)) estimated that the systemic in vivo exposure forthis extended-release composition would be 88% of the systemic exposureachieved with this IR dosing scheme.

Example 19 In Silico Modeling for Gastric Retentive Extended-Release(GR-ER) Tablet Formulation

In silico modeling was conducted using GastroPlus™ (copyright 2001-2010Simulations Plus Inc.) to develop a simulated plasma concentrationprofile for a hypothetical gastric retentive extended-release (GR-ER)tablet formulation concept. All formulation doses used were asviloxazine base.

The GR-ER tablet (dose strength 150 mg) is designed to be retained inthe stomach for up to 4 hours after ingestion after which the remainingdosage form and all undissolved drug is released into the duodenum totransit through the gastrointestinal tract. The in-vitro dissolutionprofile used for the GR-ER tablet releases 80% of the dose of drugcontained in the dosage form in approximately 10 hours.

FIG. 23 presents the comparison of the steady state simulated plasmaprofiles for an immediate release 50 mg viloxazine dosage form dosedevery 8 hours (TID) to that of the GR-ER tablet composition dosed qd.Pharmacokinetic analysis of the simulated profile for a dosing cycle of24 hours (AUC_(tau)) estimated that the systemic in vivo exposure forthis GR-ER tablet composition would be 98% of the systemic exposureachieved with this IR dosing scheme.

Example 20 Viloxazine Capsules Containing Extended Release Pellets

The Viloxazine ER-F Pellets of Example 14 (Table 13) can be filled intosize 00 capsules to produce a 300 mg viloxazine dose strength capsule orinto size 000 capsules to produce a 400 mg viloxazine dose strengthcapsule (viloxazine doses as viloxazine base).

Example 21 Additional Matrix Tablet Formulations

Final tablet blend PD0348-075 (Table 16) was compressed into 50 mg dosestrength tablets (dose as viloxazine base). Tablets were evaluated foraverage viloxazine content (n=2) and drug release testing at pH 1.1 andpH 6.8. The average content value was 99.2% label claim. The drugrelease profiles at pH 1.1 and pH 6.8 exhibited t₈₀ values ofapproximately 8 hours.

TABLE 16 Formulation PD0348-075 Compressed Tablet ^(a) Usage (%w/w)Viloxazine Hydrochloride 28.84 METHOCEL ™ K15M Premium CR 29.99 POLYOX ™WSR 303 19.99 Avicel ® PH 101 14.14 Methocel E5 Premium LV 3.00 Talc,USP 3.04 Magnesium Stearate, NF 1.00 Total 100 ^(a) Drug load 29% (w/w)viloxazine hydrochloride

The formulation in Table 16 can be modified as described in Table 17 topotentially extend the drug release profile t₈₀ value beyond 8 hours.

TABLE 17 Formulation PD0348-075 Compressed Tablet ^(a) Usage (%w/w)Viloxazine Hydrochloride 25.00 METHOCEL ™ K100M Premium CR 35.00POLYOX ™ WSR 303 30.00 Avicel ® PH 101 5.00 Methocel E5 Premium LV 3.00Talc, USP 1.00 Magnesium Stearate, NF 1.00 Total 100 ^(a) Drug load 25%(w/w) viloxazine hydrochloride

Example 24 High Drug Load Extended Release Pellet Formulation

A higher drug load extended release pellet formulation can be producedby coating the immediate release pellet formulation produced by thegranulation described in Table 6 of Example 5 with Surelease® E-7-19010to 5% (w/w). The resulting pellet dosage form will have a viloxazinehydrochloride drug load of 71% (w/w).

Example 25 Extended Release Pellet Formulation

The immediate release pellets seal coated with Opadry® II White(33G28523) to a 5% weight gain were subsequently coated with EUDRAGIT®NE 30 D containing Povidone, USP (at a ratio of 9:1 EUDRAGIT® NE 30 Dsolids to Povidone, USP solids) to a weight gain of 10% (w/w) producingan extended release pellet formulation exhibiting a t₈₀ value of between3 hours and 4 hours (FIG. 24).

Example 26

Clinical Study to Evaluate the Efficacy of Viloxazine in Adults withADHD

A randomized, double blind, multicenter, placebo controlled clinicalstudy was conducted to evaluate the efficacy of viloxazine in adultswith ADHD. During the five week treatment phase subjects wereadministered two 50 mg viloxazine capsules (formulation of Example 13,Table 9) TID for a total daily dose of 300 mg viloxazine base. Subjectsnot tolerating the 300 mg/day dose were allowed at any time of thetreatment phase to down titrate to 1 capsule TID for a total daily doseof 150 mg viloxazine base. Subjects completing the study had the optionto enroll in the PK portion of the study where at the last clinic visitplasma samples were obtained from each subject pre-dose and followingthe administration of either 50 mg viloxazine (4 subjects) or 100 mgviloxazine (14 subjects) representing the first dose of the next dosingday. Plasma samples were obtained up to six hours following dosing.

The results of the study indicated that the steady state viloxazineplasma levels achieved at both the 150 mg and the 300 mg total dailydose demonstrated clinical efficacy. The mean plasma concentrationobserved for the 4 subjects receiving the 50 mg viloxazine dose at thelast clinic visit ranged from 0.5 μg/mL to 1.6 μg/mL over the 6 hoursampling period. The mean plasma concentration observed for the 14subjects receiving the 100 mg viloxazine dose at the last clinic visitranged from 0.5 μg/mL to 2.1 μg/mL over the 6 hour sampling period.

Example 27 Viloxazine Granulation Formulation for PreparingExtruded/Spheronized Pellets

Granulation formulation (Table 18) was manufactured employing a processsimilar to that used for formulation PD348-099 of Example 5. Thegranulation was subsequently processed into pellet lot PD0385-010 byextrusion and spheronization. A seal coat of Opadry® II White (33G28523)was applied to the pellets using a Wurster process on a GPCG-1. The sealcoated pellet lot PD0385-030 was processed into extended release pellets(lot PD0385-033) by the application of an XR coating system ofSurelease® E-7-19010 containing the pore former, METHOCEL™ E5 Premium LVat the ratio of 9:1 using a Wurster process on a GPCG-1.

TABLE 18 Granulation Formulation PD0385-010 Component Usage (% w/w)Viloxazine Hydrochloride 71.30 Avicel ® PH 101 14.30 Dicalcium PhosphateDihydrate, USP 9.60 METHOCEL ™ E5 Premium LV 1.40 Povidone, USP (K-value30) 1.00 Talc, USP 2.40 Total 100

Example 28 Multiparticulates of Viloxazine by Drug Layering—LowerPotency Pellet

Multiparticulate pellets of viloxazine were prepared using a druglayering technique. The drug layering dispersion formulation (Table 19)was prepared by first dissolving 2.18 g of METHOCEL™ E5 Premium LV in1436.92 g of water with the aid of a propeller mixer. The viloxazinehydrochloride (311.53 g) was then added to the METHOCEL™ E5 Premium LVsolution and mixed for approximately one hour.

TABLE 19 Drug Dispersion Formulation PD0387-085 Component Usage (% w/w)Viloxazine Hydrochloride 17.43 METHOCEL ™ E5 Premium LV 2.18 Water 80.39Total 100

After mixing, the dispersion was screened through an 80 mesh sieve andthen using a Wurster process on a GPCG-1 the dispersion was applied to1000 g of sugar spheres (30/35 mesh) producing the drug layered pelletlot PD0387-085. The finished drug layered pellet lot had a drug contentvalue of 20% (w/w). The drug layered pellet lot was then seal coatedusing a Wurster process on a GPCG-1 to a 5% (w/w) coating level withOpadry® II White (33G28523) resulting in a drug content value of 18.7%(w/w). The seal coated pellet lot (PD0387-094) was processed into theextended release pellet lot PD0387-096 by the application of the XRcoating system of Surelease® E-7-19010 containing the pore former,METHOCEL™ E5 Premium LV at the ratio of 9:1 to a level of 14% (w/w)using a Wurster process on a GPCG-1. The extended release pellets wereoven cured at 70° C. for 48 hours. The drug content value for theextended release pellet lot was determined to be 16% (w/w). The extendedrelease pellet lot was also evaluated for drug release (FIG. 25). Thedrug release profile was near zero-order release over the interval of 0hours to 6 hours with a t₈₀ value of 6 hours.

Example 29 Multiparticulates of Viloxazine by Drug Layering—HigherPotency Pellet

The drug layered pellet lot PD0387-113 was produced by drug layering thedrug dispersion formulation listed in Table 19 on 30/35 mesh sugarspheres using a Wurster process on a GPCG-1 to the drug content value of41% (w/w). The drug layered pellet lot was then seal coated using aWurster process on a GPCG-1 to a 5% (w/w) coating level with Opadry® IIWhite (33G28523) resulting in a drug content value of 39% (w/w). Theseal coated pellet lot (PD0387-117) was processed into the extendedrelease pellet lot PD0387-119 by the application of the XR coatingsystem of Surelease® E-7-19010 containing the pore former, METHOCEL™ E5Premium LV at the ratio of 9:1 to a level of 16% (w/w) using a Wursterprocess on a GPCG-1. The extended release pellets were oven cured at 60°C. for 48 hours and the drug content value and the drug release profilewere determined. The drug content value was determined to be 33% (w/w).The drug release profile (FIG. 26) exhibited a t₈₀ value of 24 hours.

Although the foregoing refers to particular preferred embodiments, itwill be understood that the present invention is not so limited. It willoccur to those of ordinary skill in the art that various modificationsmay be made to the disclosed embodiments and that such modifications areintended to be within the scope of the present invention.

All of the publications, patent applications and patents cited in thisspecification are incorporated herein by reference in their entirety.

1. A pharmaceutical formulation, comprising (a) an immediate release(IR) component comprising viloxazine and, optionally, a pharmaceuticallyacceptable excipient, (b) a delayed release (DR) component comprising(i) viloxazine or a salt thereof, (ii) an extended release (XR) matrixhaving at least one release rate controlling compound, (iii) a layercomprising an enteric compound surrounding the matrix.
 2. Theformulation of claim 1, wherein the XR matrix component comprises fromabout 30% (w/w) to about 60% (w/w) of viloxazine.
 3. The formulation ofclaim 1, wherein the XR matrix component is in the form of a pluralityof particles.
 4. The formulation of claim 1, wherein the release ratecontrolling compound is present in an amount of 5% (w/w) to 65% (w/w) ofthe XR matrix component.
 5. The formulation of claim 1, wherein therelease rate controlling compound in the XR matrix component is selectedfrom the group consisting of ethylcellulose; cellulose acetate;cellulose acetate butyrate; waxes; hydrogenated vegetable oils; glycerylbehenate; glyceryl palmitostearate; PEG glyceryl esters; poly(ethylacrylate-co-methyl methacrylate) ethyl acrylate methyl methacrylatecopolymer; poly (ethyl acrylate-co-methylmethacrylate-cotrimethylammonioethyl methacrylate chloride); polyvinylacetate; cellulose acetate propionate, and combinations thereof.
 6. Theformulation of claim 1, wherein the enteric compound is selected fromthe group consisting of poly(methyl acrylate-co-methylmethacrylate-co-methacrylic acid), poly(methacrylic acid-co-methylmethacrylate), hydroxypropyl methylcellulose acetate succinate,hydroxypropyl methylcellulose phthalate, cellulose acetate phthalate,shellac, zein, and combinations thereof.
 7. The formulation of claim 1for once-a-day administration.
 8. The formulation of claim 1 fortwice-a-day administration.
 9. The formulation of claim 1, comprisingfrom 10 mg to 800 mg of viloxazine.
 10. The formulation of claim 1,wherein the viloxazine salt comprises viloxazine hydrochloride.
 11. Theformulation of claim 1, wherein the formulation provides for a maximumsteady state plasma concentration (C_(max)) of viloxazine which ishigher than the minimal therapeutically effective concentration andwhich is in the range of 80% to 125% relative to the maximum plasmaconcentration produced by administration of viloxazine as an IRformulation TID or BID.
 12. The formulation of claim 1, wherein theformulation provides for relative steady state area under the viloxazineplasma concentration time profiles for a 24 hour dosing interval(AUC_(tau)) in the range of 80% to 125% as compared to viloxazineadministered as an immediate release formulation TID or BID.
 13. Theformulation of claim 1 in a dosage form selected from tablets, capsules,beads, granules, powders, caplets, troches, sachets, cachets, pouches,and sprinkles.
 14. A pharmaceutical formulation, comprising: (a) animmediate release (IR) component comprising an inert core and a layercomprising viloxazine and, optionally, a pharmaceutically acceptableexcipient, surrounding the core, (b) a delayed release (DR) componentcomprising: (i) an inert core, (ii) a first layer comprising viloxazineor a salt thereof and, optionally, a pharmaceutically acceptableexcipient, surrounding the core, and (iii) a second layer comprising atleast one release rate controlling compound surrounding the first layer,and (iv) a third layer comprising an enteric compound surrounding thesecond layer.
 15. The formulation of claim 14, wherein the DR componentcomprises from about 25% (w/w) to about 75% (w/w) of viloxazine.
 16. Theformulation of claim 14, wherein the DR component is in the form of aplurality of particles.
 17. The formulation of claim 14, wherein the atleast one release rate controlling compound is present in an amount of5% (w/w) to 65% (w/w) of the DR component.
 18. The formulation of claim14, wherein the at least one release rate controlling compound isselected from the group consisting of ethylcellulose; cellulose acetate;cellulose acetate butyrate; waxes; hydrogenated vegetable oils; glycerylbehenate; glyceryl palmitostearate; PEG glyceryl esters; poly(ethylacrylate-co-methyl methacrylate) ethyl acrylate methyl methacrylatecopolymer; poly (ethyl acrylate-co-methylmethacrylate-cotrimethylammonioethyl methacrylate chloride); polyvinylacetate; cellulose acetate propionate, and combinations thereof.
 19. Theformulation of claim 14, wherein the second layer of the DR componentfurther comprises at least one pore former.
 20. The formulation of claim19, wherein the weight ratio of release rate controlling compound topore former is 19:1 to 8.5:1.5.
 21. The formulation of claim 20, whereinthe pore former is selected from the group consisting of povidone,hypromellose, hydroxyethyl cellulose, hydroxypropyl cellulose, andorganic acids.
 22. The formulation of claim 14, wherein the entericcompound is selected from the group consisting of poly(methylacrylate-co-methyl methacrylate-co-methacrylic acid), poly(methacrylicacid-co-methyl methacrylate), hydroxypropyl methylcellulose acetatesuccinate, hydroxypropyl methylcellulose phthalate, cellulose acetatephthalate, shellac, zein, and combinations thereof.
 23. The formulationof claim 14 for once-a-day administration.
 24. The formulation of claim14 for twice-a-day administration.
 25. The formulation of claim 14,comprising from 10 mg to 800 mg of viloxazine.
 26. The formulation ofclaim 14, wherein the viloxazine salt comprises viloxazinehydrochloride.
 27. The formulation of claim 14, wherein the formulationprovides for a maximum steady state plasma concentration (C_(max)) ofviloxazine which is higher than the minimal therapeutically effectiveconcentration and which is in the range of 80% to 125% relative to themaximum plasma concentration produced by administration of viloxazine asan IR formulation TID or BID.
 28. The formulation of claim 14, whereinthe formulation provides for relative steady state area under theviloxazine plasma concentration time profiles for a 24 hour dosinginterval (AUC_(tau)) in the range of 80% to 125% as compared toviloxazine administered as an immediate release formulation TID or BID.29. The formulation of claim 14 in a dosage form selected from tablets,capsules, beads, granules, powders, caplets, troches, sachets, cachets,pouches, and sprinkles.